metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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trans-Di­bromidobis(1-ethyl-3-methyl­imidazol-2-yl­­idene)palladium(II)

aDepartment of Chemistry & Center for Materials Crystallography, Aarhus University, Aarhus, Denmark
*Correspondence e-mail: bo@chem.au.dk

(Received 22 July 2011; accepted 28 July 2011; online 6 August 2011)

The title compound, trans-[PdBr2(C6H10N2)2], was synthesized ionothermally in the ionic liquid solvent 1-ethyl-3-methyl­imidazolium bromide. In the crystal, the PdII atoms are square-planarly coordinated to two Br atoms and two neutral (C6H10N2) ligands. The PdII atom is located on an inversion centre.

Related literature

The title complex shares many features with a number of known structures, which also contain a PdII atom square-planarly coordinated to two bromide ligands in trans-conformation as well as two equivalent organic ligands (Hahn et al., 2004[Hahn, F. E., Heidrich, B., Lugger, T. & Pape, T. (2004). Z. Naturforsch. Teil B, 59, 1519.]; Huynh & Wu, 2009[Huynh, H. V. & Wu, J. (2009). J. Organomet. Chem. 694, 323-331.]). A few of these structures even have the same space group and in some structures the organic ligand is also an imidazolium derivative (Dash et al., 2010[Dash, C., Shaikh, M. M., Butcher, R. J. & Ghosh, P. (2010). Dalton Trans. 39, 2515-2524.]). The title compound was obtained in a attempt to simplify the synthesis of the cis-complex which was described previously (Madsen et al., 2011[Madsen, S. R., Lock, N., Overgaard, J. & Iversen, B. B. (2011). In preparation.]). For information on the ionothermal synthesis method, see: Welton (1999[Welton, T. (1999). Chem. Rev. 99, 2071-2083.]); Babai & Mudring (2006[Babai, A. & Mudring, A. (2006). Inorg. Chem. 45, 4874-4876.]); Morris (2009[Morris, R. E. (2009). Chem. Commun. pp. 2990-2998.]).

[Scheme 1]

Experimental

Crystal data
  • [PdBr2(C6H10N2)2]

  • Mr = 486.54

  • Monoclinic, P 21 /n

  • a = 8.3093 (2) Å

  • b = 8.6868 (2) Å

  • c = 12.0788 (3) Å

  • β = 101.741 (1)°

  • V = 853.62 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 5.76 mm−1

  • T = 296 K

  • 0.15 × 0.15 × 0.1 mm

Data collection
  • Bruker X8 APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2008a[Sheldrick, G. M. (2008a). SADABS. University of Göttingen, Germany.]) Tmin = 0.585, Tmax = 0.711

  • 27485 measured reflections

  • 2582 independent reflections

  • 1894 reflections with I > 2σ(I)

  • Rint = 0.022

Refinement
  • R[F2 > 2σ(F2)] = 0.044

  • wR(F2) = 0.167

  • S = 1.63

  • 2582 reflections

  • 88 parameters

  • H-atom parameters constrained

  • Δρmax = 1.84 e Å−3

  • Δρmin = −1.02 e Å−3

Table 1
Selected geometric parameters (Å, °)

C1—Pd1 2.023 (4)
Br1—Pd1 2.4364 (5)
C1—Pd1—C1i 180
C1—Pd1—Br1 89.14 (12)
C1i—Pd1—Br1 90.86 (12)
Br1—Pd1—Br1i 180
Symmetry code: (i) -x+2, -y+2, -z+2.

Data collection: APEX2 (Bruker, 2011[Bruker (2011). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2011[Bruker (2011). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b[Sheldrick, G. M. (2008b). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b[Sheldrick, G. M. (2008b). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Mol. Struct. 609, 97-108.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Related literature top

The title complex shares many features with a number of known structures, which also contain a square planar Pd atom coordinated to two bromide ligands in trans-conformation as well as two equivalent organic ligands (Hahn et al., 2004; Huynh & Wu, 2009). A few of these structures even have the same space group and in some structures the organic ligand is also an imidazolium derivative (Dash et al., 2010). The title compound was obtained in a attempt to simplify the synthesis of the cis-complex which was described previously (Madsen et al., 2011). For information on the ionothermal synthesis method, see: Welton (1999); Babai & Mudring (2006); Morris (2009).

Experimental top

The title compound was obtained when palladium(II) acetate and 1-ethyl-3- methylimidazolium bromide were mixed and heated in an autoclave at 100°C for 8 days.

Refinement top

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.95–0.99 Å and with Uiso(H) = 1.2 times Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2011); data reduction: SAINT (Bruker, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of trans-[PdBr2(C6H10N2)2], with atom labels and 50% probability displacement ellipsoids for non-H atoms.
trans-Dibromidobis(1-ethyl-3-methylimidazol-2-ylidene)palladium(II) top
Crystal data top
[PdBr2(C6H10N2)2]F(000) = 472
Mr = 486.54Dx = 1.893 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 9872 reflections
a = 8.3093 (2) Åθ = 5.5–54.7°
b = 8.6868 (2) ŵ = 5.76 mm1
c = 12.0788 (3) ÅT = 296 K
β = 101.741 (1)°Square, colourless
V = 853.62 (4) Å30.15 × 0.15 × 0.1 mm
Z = 2
Data collection top
Bruker X8 APEXII
diffractometer
2582 independent reflections
Radiation source: fine-focus sealed tube1894 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.022
Detector resolution: 12.00 pixels mm-1θmax = 30.5°, θmin = 2.7°
Narrow slices collected using ϕ and ω scansh = 1111
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
k = 1212
Tmin = 0.585, Tmax = 0.711l = 1517
27485 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.167H-atom parameters constrained
S = 1.63 w = 1/[σ2(Fo2) + (0.0705P)2]
where P = (Fo2 + 2Fc2)/3
2582 reflections(Δ/σ)max = 0.008
88 parametersΔρmax = 1.84 e Å3
0 restraintsΔρmin = 1.02 e Å3
Crystal data top
[PdBr2(C6H10N2)2]V = 853.62 (4) Å3
Mr = 486.54Z = 2
Monoclinic, P21/nMo Kα radiation
a = 8.3093 (2) ŵ = 5.76 mm1
b = 8.6868 (2) ÅT = 296 K
c = 12.0788 (3) Å0.15 × 0.15 × 0.1 mm
β = 101.741 (1)°
Data collection top
Bruker X8 APEXII
diffractometer
2582 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
1894 reflections with I > 2σ(I)
Tmin = 0.585, Tmax = 0.711Rint = 0.022
27485 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.167H-atom parameters constrained
S = 1.63Δρmax = 1.84 e Å3
2582 reflectionsΔρmin = 1.02 e Å3
88 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N20.8710 (5)0.9917 (3)0.7471 (3)0.0598 (9)
C10.9896 (5)0.9475 (5)0.8355 (3)0.0570 (8)
C30.9059 (7)0.9436 (6)0.6478 (4)0.0735 (11)
H30.84110.95940.57630.088*
C51.2461 (7)0.7839 (10)0.8505 (6)0.118 (2)
H5A1.22690.7470.92250.142*
H5B1.26750.69580.80620.142*
C21.0451 (6)0.8718 (7)0.6700 (4)0.0852 (14)
H21.10020.82940.61760.102*
C61.3777 (13)0.8815 (14)0.8675 (10)0.197 (5)
H6A1.4730.82890.90840.295*
H6B1.35480.96910.91040.295*
H6C1.39770.91520.79590.295*
C40.7242 (7)1.0768 (7)0.7604 (5)0.0953 (17)
H4A0.65721.09730.68730.143*
H4B0.75631.17230.79860.143*
H4C0.66291.01660.80410.143*
Br11.09068 (7)1.25854 (6)0.96387 (4)0.0893 (2)
N11.0978 (4)0.8699 (5)0.7886 (3)0.0772 (10)
Pd11110.0555 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N20.075 (2)0.060 (2)0.0438 (19)0.0033 (13)0.0110 (16)0.0020 (13)
C10.064 (2)0.063 (2)0.047 (2)0.0089 (17)0.0168 (16)0.0047 (18)
C30.104 (4)0.073 (3)0.044 (2)0.009 (3)0.016 (2)0.002 (2)
C50.080 (3)0.189 (7)0.088 (4)0.017 (4)0.023 (3)0.011 (4)
C20.100 (4)0.104 (4)0.059 (3)0.001 (3)0.033 (3)0.006 (3)
C60.136 (7)0.207 (12)0.231 (13)0.009 (9)0.000 (7)0.036 (9)
C40.104 (4)0.114 (4)0.064 (3)0.052 (4)0.010 (3)0.006 (3)
Br10.1261 (5)0.0831 (4)0.0624 (4)0.0312 (3)0.0278 (3)0.0070 (2)
N10.0732 (19)0.108 (3)0.0529 (19)0.008 (2)0.0181 (16)0.0060 (19)
Pd10.0597 (3)0.0696 (4)0.0386 (3)0.00208 (16)0.01357 (18)0.00364 (15)
Geometric parameters (Å, º) top
N2—C11.353 (6)C2—N11.410 (6)
N2—C31.356 (6)C2—H20.93
N2—C41.463 (6)C6—H6A0.96
C1—N11.338 (5)C6—H6B0.96
C1—Pd12.023 (4)C6—H6C0.96
C3—C21.293 (7)C4—H4A0.96
C3—H30.93C4—H4B0.96
C5—C61.366 (12)C4—H4C0.96
C5—N11.503 (7)Br1—Pd12.4364 (5)
C5—H5A0.97Pd1—C1i2.023 (4)
C5—H5B0.97Pd1—Br1i2.4364 (5)
C1—N2—C3111.0 (4)H6A—C6—H6B109.5
C1—N2—C4123.1 (4)C5—C6—H6C109.5
C3—N2—C4125.9 (4)H6A—C6—H6C109.5
N1—C1—N2104.7 (3)H6B—C6—H6C109.5
N1—C1—Pd1129.1 (3)N2—C4—H4A109.5
N2—C1—Pd1126.2 (3)N2—C4—H4B109.5
C2—C3—N2107.9 (4)H4A—C4—H4B109.5
C2—C3—H3126N2—C4—H4C109.5
N2—C3—H3126H4A—C4—H4C109.5
C6—C5—N1108.5 (8)H4B—C4—H4C109.5
C6—C5—H5A110C1—N1—C2109.1 (4)
N1—C5—H5A110C1—N1—C5126.4 (4)
C6—C5—H5B110C2—N1—C5124.3 (4)
N1—C5—H5B110C1—Pd1—C1i180.000 (2)
H5A—C5—H5B108.4C1—Pd1—Br189.14 (12)
C3—C2—N1107.2 (4)C1i—Pd1—Br190.86 (12)
C3—C2—H2126.4C1—Pd1—Br1i90.86 (12)
N1—C2—H2126.4C1i—Pd1—Br1i89.14 (12)
C5—C6—H6A109.5Br1—Pd1—Br1i180
C5—C6—H6B109.5
C3—N2—C1—N10.5 (5)Pd1—C1—N1—C58.6 (7)
C4—N2—C1—N1178.1 (4)C3—C2—N1—C12.4 (6)
C3—N2—C1—Pd1176.8 (3)C3—C2—N1—C5173.7 (5)
C4—N2—C1—Pd14.7 (6)C6—C5—N1—C191.6 (8)
C1—N2—C3—C21.1 (6)C6—C5—N1—C293.0 (8)
C4—N2—C3—C2179.6 (5)N1—C1—Pd1—Br1100.3 (4)
N2—C3—C2—N12.1 (6)N2—C1—Pd1—Br176.2 (4)
N2—C1—N1—C21.7 (5)N1—C1—Pd1—Br1i79.7 (4)
Pd1—C1—N1—C2175.4 (3)N2—C1—Pd1—Br1i103.8 (4)
N2—C1—N1—C5174.3 (5)
Symmetry code: (i) x+2, y+2, z+2.

Experimental details

Crystal data
Chemical formula[PdBr2(C6H10N2)2]
Mr486.54
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)8.3093 (2), 8.6868 (2), 12.0788 (3)
β (°) 101.741 (1)
V3)853.62 (4)
Z2
Radiation typeMo Kα
µ (mm1)5.76
Crystal size (mm)0.15 × 0.15 × 0.1
Data collection
DiffractometerBruker X8 APEXII
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2008a)
Tmin, Tmax0.585, 0.711
No. of measured, independent and
observed [I > 2σ(I)] reflections
27485, 2582, 1894
Rint0.022
(sin θ/λ)max1)0.714
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.167, 1.63
No. of reflections2582
No. of parameters88
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.84, 1.02

Computer programs: APEX2 (Bruker, 2011), SAINT (Bruker, 2011), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
C1—Pd12.023 (4)Br1—Pd12.4364 (5)
C1—Pd1—C1i180.000 (2)C1i—Pd1—Br190.86 (12)
C1—Pd1—Br189.14 (12)Br1—Pd1—Br1i180
Symmetry code: (i) x+2, y+2, z+2.
 

Acknowledgements

The authors thank the Center for Materials Crystallography (CMC) for financial support.

References

First citationBabai, A. & Mudring, A. (2006). Inorg. Chem. 45, 4874–4876.  Web of Science CSD CrossRef CAS Google Scholar
First citationBruker (2011). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDash, C., Shaikh, M. M., Butcher, R. J. & Ghosh, P. (2010). Dalton Trans. 39, 2515–2524.  CSD CrossRef CAS Google Scholar
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First citationHuynh, H. V. & Wu, J. (2009). J. Organomet. Chem. 694, 323–331.  Web of Science CSD CrossRef CAS Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Mol. Struct. 609, 97–108.  Google Scholar
First citationMadsen, S. R., Lock, N., Overgaard, J. & Iversen, B. B. (2011). In preparation.  Google Scholar
First citationMorris, R. E. (2009). Chem. Commun. pp. 2990–2998.  Web of Science CrossRef Google Scholar
First citationSheldrick, G. M. (2008a). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008b). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWelton, T. (1999). Chem. Rev. 99, 2071–2083.  Web of Science CrossRef PubMed CAS Google Scholar

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